The retailer on Tuesday rolled out a major upgrade to its mobile shopping app that allows its pharmacy customers to quickly and simply order refills, track those orders and their costs. And to sweeten up the incentives to use the app, Walmart will be setting up “express lanes” in the pharmacies to customers who have placed orders via the app. That is aimed at addressing a long time irritant—lengthy waits in line—but perhaps just as importantly, to give shoppers more reason to use the Walmart app, a key tool in the discounter’s battle with Amazon.com (AMZN).

The express lanes will be at almost all of Walmart’s 4,700 stores by the fall.

The move is just the latest to make Walmart’s shopping app “stickier” in the hopes consumers will stay and make their digital purchases there, rather than at amazon.com or target.com for instance. Last year, Walmart rolled out the Walmart Pay app for the same reason. As of last summer, 30 million people a month used the Walmart app now, according to comScore, making it one of the most used shopping apps, on par with EBay, (EBAY) but well behind Amazon.

“Our customers continue to tell us that the need to save time has become just as important as the need to save money,” Daniel Eckert, senior vice president at Walmart Services, said at a media briefing and demo on Monday at a store in North Bergen, N.J.

P. Wahba

Improving the app is also a way to safeguard Walmart’s prominent position in the prescription business.

According to Pembroke Consulting data, Walmart is the fourth largest pharmacy operator in the U.S., with 2016 sales of $20.6 billion, making it larger than drugstore chain Rite Aid. (RAD) Industry leader CVS Health (CVS) added many of the same functions to its own app Walmart has a year and a half ago, adding to the urgency. Along with the grocery section, the pharmacy is one of the most important parts of a store for bringing in shoppers and helping retailers like Walmart improve store traffic.

The retailer announced another change to the shopping app with similar aims. Walmart is simplifying the process for its workers to process the paperwork related to money transfers or bill payments or other financial services in its stores, services that are used at some point or other in the year by 20% of its customers. Eckert told reporters lines could sometimes exceed one hour, particularly during high traffic times like tax season or when paychecks are handed out, and something likely to vex shoppers.

Walmart recently reported its ninth straight quarter of hard-won comparable sales gains. And perhaps more importantly, its online growth has re-acclerated. The company is betting heavily on its app to help keep that streak going.